- Step sequencer with gate, trigger and CV outputs.
- Very very very easy to build, not programming needed.
- Expandable until the infinite and more!
- Configurable in a minimum of 4 steps (this is the bad part, not possible to reduce to 1, 2 o 3 steps. The minimum are 4 ad multiple).
- More than one sequence at a time! (see the video)
- Very funny and easy to use.
- Reduce the level of stress in a 110% in comparison with computer based sequences.
- Fat free.

The circuit is very simple and is like most of the other simple 4017 sequencers that are around the world:

- The clock signal is provided by a 555. it is possible to add a smaller pot in series with the 1M to adjust the fine frequency.

- The S1 and S2 switches are pushbuttons and are for send the first step to the 4015 and reset it respectively.

- The 4015 circuit is very simple. every 4015 have 2 4 bit static shift registers. each circuit have data, clock, reset inputs and 4 outputs. Whan a voltage "on" is send to the data "in" and after the first cycle of the clock has passed a voltage "on" is send to the 1st out, then to de 2nd and so. If we chain the 4th out with the data in of the nex circuit we have 4 steps more. So we can build an infinite step sequencer.

The bad part, or the antifeature (like says Ray Wilson) is that you can only run the seq in blocks of 4 steps, not less.

The other good and incidental feature is that if you push more times the data switch you send another sequence to the circuit so more than one sequence can be running at the time creating interesting pseudorandom sequences when the differents sequences coincide.

- The other parts are very simple. Each channel have a led with a simple 2n3904 circuit, a pot that goes directly to CV out and a switch to activate the gate out.

Then the gate out is mixed with the clock signal into an AND gate (in my case I have used to NAND because I had a 4011 IC there) to out the pulse signal.

- The circuit can run from 9v to theorichaly 18. I ave tested it from 9 to 12 and its fine. Of course the CV out will change if the power supply voltage changes.

Filter caps can be added, (it's a good idea) for the power.

and that's all.

PCBs soon!!

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Last edited by papaver on Tue May 15, 2012 4:43 am; edited 1 time in total

Nice one, I hadn't seen a sequencer using the 4015 before, but the fact that it is easily expandable is very nice. It would need some buffering, and a schmitt trigger to trigger it is also very helpful since it'll allow you to use small signals to trigger as well. I'd also go with a CMOS 555 (or no clock at all).

Yes, the buffer section is not in the schematic, but it'll be in the final version. It'll be usefull in some circumstances. But for now it works fine with only one destination and short cables.

Don't understand what you mean with the schmitt trigger. I have tried to use a 40106 (6 schmit trgis) for the clock, but Ive noticed some irregularities with the tempo, maye is for the lack of filtering capacitors during the tests or for the lack of the buffers at the outputs, I don't know.

But using a 40106 would be great since with a pair of schmith triggers you can build any logic gate that you want. So you put the clock and the AND gate in one single chip.

Anyway the save in money and space doing this is not significant as the build is very easy.

The bad part, or the antifeature (like says Ray Wilson) is that you can only run the seq in blocks of 4 steps, not less.

Or can you?

If the D input of IC1b were connected to QC instead of QD of IC1a. the sequence would be shortened by one step. Connecting to QB would shorten by two steps. The "skipped" steps would occur simultaneously with the first n steps of the following shift register. The resulting voltage outputs would then be additive. (Think: KLEE.) Or, the voltages from the skipped steps could be eliminated by simply turning down the appropriate pots.

With enough switches or patch cords you should be able to get any length from 4 to 16 steps._________________"I’m a New Yorker, and I know a con when I see one.” -- Michael Bloomberg

At the beggining I have think about this. Like in a normal sequencer if I connect the step 15 or 14 to the D of Ic1A, but the concept of the simultaneous steps don't like me then so I decided to don't look anymore to this. But your point is really new in perspective. (And a lesson to review my way of thinking )

if you made those D inputs switchable to each of the 4 Q outputs could be very interesting indeed especially if 4016 or 4066 switches were used controlled by some extra logic circuitry and/ or physical switches plus a VC in jack added [a comparative setup perhaps ? ]
dont ya just love feature creep
but it would make for an orsm N step sequencer_________________In an infinite universe one might very well
ask where the hell am I
oh yeah thats right the land of OZ
as good an answer as any

For now I will release the Centipede v1 with the mecanic switches. I will post the schematics soon with the switches and the buffers. I want to keep this one simple.

Anyway, I will develop another sequencer, with more features, based on this one, but I need more time.

First the v1!

cool I will look forward to it
and it takes so much time I understand that part all too well
goodluck_________________In an infinite universe one might very well
ask where the hell am I
oh yeah thats right the land of OZ
as good an answer as any

Yes this is very clos to the centipede. Is a very simple build but it can be the center of something more complex.

I've developed the PCB but for now I have stopped the project for a while. I have to much work here now and no time. As soon as I can I will share everything and work on a v.2 with some cool options (still in my mind ).

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